Johnk, the Desolate

Trample, haste
Sacrifice X creatures: Johnk, the Desolate exiles target creature with toughness X until Johnk leaves the battlefield. That creatures controller may choose to sacrifice X creatures to return it to the battlefield under their control.
Johnk, the Desolate gets +X/+X where X is the combined toughness of all creatures exiled by Johnk, the Desolate.
"What didn't belong to Johnk, Johnk gave up what he had to get."